Fluorinated lubricant additives

ABSTRACT

Fluorinated dialkyl dithiophosphoric acids according to formula (I) and metallic salts thereof:  
                 
 
     the compounds are useful, for example, as additives for lubricant compositions.

FIELD OF INVENTION

[0001] This invention relates to lubricant additives that provideanti-wear and friction-reducing properties when incorporated intolubricant compositions or other compositions where such properties aredesired, such as motor oils.

BACKGROUND ART

[0002] A significant source of deterioration in machinery such asengines and motors that contain moving parts in mechanical motion athigh temperatures is friction and wear between the contact surfaces ofthe moving parts. Such deterioration is particularly evident at startupand shutdown of the machinery. To combat these problems, lubricatingagents such as lubricating oils, waxes and greases have traditionallybeen applied to the moving contact surfaces to prevent wear and toreduce friction.

[0003] Reducing or controlling friction is particularly important inmotor oils, including automobile motor oils, because of the need toreduce wear, and also because this wear reduction must be accomplishedwhile at the same time meeting standards for fuel economy as well asenvironmental vehicle fuel emissions control. Because of increasedgovernment regulation of vehicle fuel emissions, efforts have been madeto improve engine performance, including improving engine design andemissions catalyst performance, as well as developing better additivessuch as lubricants and engine oil additives.

[0004] Ideally, a lubricant should provide lubrication of the entirecontact surface. Such full-film contact is preferably achieved bycompletely coating the surfaces of the moving parts such that the partsnever make contact. However, developing a full-film lubricant that iseffective under the severe operating conditions of most engines andmotors containing moving parts, has posed several difficulties. Designconstraints, together with high load, slow speed, lubricant starvation,or low viscosity of the lubricant, may preclude full-film lubricationand increase the severity of contact. These conditions are oftenunavoidable during normal operation of machinery, and are particularlysevere during startup and shutdown.

[0005] In cases where lubricants such as oils and greases cannot providefull-film lubrication at all times, anti-wear additives or frictionmodifiers are usually added. These anti-wear additives modify thesurfaces to be lubricated through adsorption or chemical reaction toform coated surfaces that are characterized by reduced friction andincreased wear resistance. It is generally recognized that differenttypes of additives may interact in positive or negative ways and therebyenhance or interfere with each other's performance. Antiwear agents andfriction modifiers in particular, because they are believed to functionby modifying the rubbing surfaces through adsorption or chemicalreaction, have a high probability of affecting each other's performance.This is because such materials adsorb on surfaces more or less stronglyand compete with one another for surface adsorption sites. A stronglyadsorbing material may exclude a more weakly adsorbing material fromcontact with the surface, thereby preventing it from exerting its effecton the surface. Such surface competition phenomena can pose significantchallenges in developing additives and creating formulations where eachadditive can achieve its desired purpose.

[0006] Many kinds of anti-wear additives are known. In particular,organic phosphorus compounds such as dialkyl dithiophosphoric acids anddialkyl dithiophosphates have been used. Some of the most widely usedand relied upon dialkyl dithiophosphates are metallic salts of dialkyldithiophosphates, such as zinc dialkyldithiophosphates (ZDDPs), whichfind application in many different types of lubricants. The alkyl groupsin zinc dialkyl dithiophosphates are typically derived fromnon-fluorinated alcohols that have been selected, based on chain lengthand degree of functional substitution, to impart desirable performancecharacteristics, such as solubility in the lubricant base fluid andthermal stability to the ZDDP. It is recognized that thesecharacteristics can be changed by careful selection of the alkyl groupsto optimize performance in particular applications.

[0007] ZDDP compositions are known to be effective in many formulations.This is evidence that they can compete very effectively for surfaceadsorption sites and thereby exert their effect on the rubbing surfaces.It might be predicted, therefore, that because ZDDPs adsorb strongly atsurfaces and form very effective antiwear films by their chemical actionat surfaces, such compounds would exclude other antiwear additives fromadsorbing and exerting their effects at the surface.

[0008] Although ZDDPs have been used for many years in passenger carmotor oil, their use is currently restricted because they containphosphorus, and the amount of this element in motor oils is limited toless than 0.1%, since the phosphorus from ZDDP poisons catalyticconverters, leading to increased vehicle emissions. It is anticipatedthat the future use of ZDDPs may be reduced even more than the currentlevel. Anti-wear additives that can be used in place of ZDDPs, or inaddition to them, are therefore of great interest.

[0009] ZDDPs have also been used in combination with certain molybdenum(Mo) additives, including soluble molybdenum additives such asmolybdenum dialkyl dithiophosphates, molybdenum dialkyl dithiocarbamatesand molybdenum amide complexes. One limitation of such ZDDP-Mo additivecombinations, however, is that the molybdenum additives frequentlyreduce the anti-wear effectiveness of the ZDDPs, which is highlyundesirable.

[0010] Other additives that may be included in lubricants as anti-wearadditives include fluorinated organic compounds. Typical fluorinatedcompounds that may be used as lubricant additives includepolytetrafluoroethylene (PTFE) and perfluoropolyether (PFPE).Fluorinated organic compounds, particularly esters and ethers, have beendisclosed as lubricants for magnetic media, for example, in JapanesePatent 259482, Japanese Patent 08259501, and U.S. Pat. Nos. 5,578,387;5,391,814 and 5,510,513.

[0011] Japanese Patent 01122026 teaches use of fluorine containingdibasic acid esters derived from diacids up to C₈ as lubricants formagnetic media. This publication, as does PCT publication, US/92/08331,teaches that the acid structure from which the diester is formed mayhave double bonds present. The molecular structures taught by each ofthese publications may also have fluorine atoms present in each of theend group.

[0012] Partly-fluorinated adipic acid diesters,R_(f)(CH₂)_(x)O₂C(CH₂)₄CO₂(CH₂)_(x)R_(f), have been disclosed aslubricating coatings by Russian patent SU 449925. Bowers et al. (Lubr.Eng., July-August, 1956, pages 245-253) studied the boundary lubricatingproperties of several similar esters. The compounds disclosed in thispublication have fluorine present in each of the diester groups, howeverthe fluorination is symmetric. These symmetric, partially fluorinatedesters have very low solubility in conventional lubricant base fluidsand are therefore, of limited utility as additives in such base fluids.

[0013] Japanese Patent 2604186 discloses 1,2,3,4-butane-tetracarboxylicacid tetraesters with partly-fluorinated alcohols, but since all fourester groups are derived from fluorinated alcohols, these esters, too,are symmetric. Other examples of the teaching of symmetricallyfluorinated molecular structures include U.S. Pat. Nos. 4,203,856;5,066,412 and 4,039,301 and in JP08259482 and JP08259501.

[0014] Fluorine-containing tri-carbonyl compounds, including someesters, are disclosed as lubricant additives in Japanese patent JP07242584, and partial fluoroesters of polycarboxylic acids, in which theacid functional groups are not completely esterified was taught in U.S.Pat. No. 3,124,533.

[0015] Fluorinated organic compounds are thought to protect metalsurfaces from wear by forming metal fluorides on the coated surfaces.Surface studies of coated metal surfaces suggest that the fluorinatedorganic compounds undergo tribochemical reactions, which arefriction-stimulated chemical reactions, with the metal surfaces to formthe metal fluoride. For example, in the case of a steel mechanism, thesurfaces of which have been lubricated with PTFE, deposits of ironfluoride have been observed in the near-surface region of the wearregion. Metal fluorides such as iron fluoride are known to have goodproperties as solid lubricants, and, accordingly, it is hypothesizedthat the metal fluoride formed by the interaction of the PTFE and themetal shears more readily than the metal itself, and is less prone toweld-fracture type of wear. As a result, use of the PTFE reducesfriction and wear in the mixed and boundary lubrication regimes, whereactual contact between the moving surfaces may occur.

[0016] Although fluorinated materials such as those described above havebeen used as lubricant additives, there are certain limitations to theirusefulness in these applications. One limitation of these fluorinatedmaterials is their very low solubility in conventional lubricant basefluids such as natural and synthetic hydrocarbons and esters, which haseffectively limited their application to use as solid additives.Although solid additives may be used in lubricants, they pose severalproblems.

[0017] For example, highly fluorinated organic compounds used aslubricants are generally insoluble in most conventional lubricant basefluids. For example, the high degree of insolubility ofperfluoropolyethers (PFPEs) makes it extremely difficult to use them asadditives in lubricant formulations. While PFPEs themselves can be usedas the lubricant base fluid, their high cost makes such a modificationprohibitively expensive. Similar insolubility problems arecharacteristic of polytetrafluoroethylene (PTFE). PTFE, which is amostly insoluble solid, can be finely dispersed as particles inlubricant base fluids to reduce friction and wear. However,effectiveness of such a dispersed solid lubricant depends on maintainingthe PTFE particles in stable dispersion. Achieving an indefinitelystable dispersion is a challenge, particularly in a formulatedlubricant, which may contain detergents, dispersants, or surfactantsthat may destabilize the PTFE dispersion. Moreover, solid particles insuspension are not very effective at forming films on the contactsurfaces of mechanical parts, and this reduces the effectiveness of thetribochemical reactions that must occur at the metal surface to providethe desired lubricity. This is in direct contrast to liquid or solublematerials that may adsorb onto the metal surfaces for which they haveaffinity, thereby modifying those surfaces directly by participating inthe surface chemical reactions that provide the lubricating effect.Particles of a dispersed solid may also flocculate in the lubricant overtime. Such flocculated particles may then plug or restrict flow of thelubricant in the equipment and result in lubricant starvation incritical locations.

[0018] In view of the deficiencies in the art, it is an object of thepresent invention to provide a fluorinated lubricant additive which canserve as an anti-wear agent and friction reducer, and which, moreover,is compatible with conventional lubricant base fluids typically used inlubricant compositions. Desirably, such a lubricant additive should alsoovercome the cost and solubility limitations of previously knownfluorinated organic compounds. This object has been achieved by thefluorinated compounds and compositions of the present invention.

DISCLOSURE OF INVENTION

[0019] The present invention provides fluorinated organic compoundsaccording to formula (I), or metallic salts thereof:

[0020] wherein R₁ and R₂ are each independently selected from the groupconsisting of C₁ to C₄₀ organic residues; and

[0021] wherein R₁ and R₂ are different, or R₁ and R₂ form a ring, and atleast one of R₁ and R₂ is a fluorinated C₁ to C₄₀ organic residue.

[0022] Another embodiment of the invention comprises a compound offormula (I), or metallic salts thereof:

[0023] wherein R₁ and R₂ are each independently selected from the groupconsisting of C₁ to C₄₀ organic residues; and

[0024] wherein R₁ and R₂ are the same or different, or R₁ and R₂ form aring, and at least one of R₁ and R₂ is a fluorinated C₁ to C₄₀ organicresidue, provided that when R₁ and R₂ are the same, neither R₁ nor R₂can be —(CH₂(CF₂)_(x)CF₂H), where x is 1, 3 or 5.

[0025] The invention further comprises an anti-wear additive comprisinga compound of formula (I), or metallic salts thereof:

[0026] wherein R₁ and R₂ are each independently selected from the groupconsisting of C₁ to C₄₀ organic residues, or R₁ and R₂ form a ring; and

[0027] wherein at least one of R₁ and R₂ is a fluorinated C₁ to C₄₀organic residue.

[0028] The present invention also provides a process of making ananti-wear additive comprising:

[0029] a) preparing a mixture of two or more compounds, wherein saidmixture includes at least one fluorinated compound and at least onenon-fluorinated compound;

[0030] b) reacting the mixture with a thiophosphorus compound to formone or more oxygen linkages between the phosphorus atom of thethiophosphorus compound and each of the fluorinated and non-fluorinatedcompounds; and

[0031] c) recovering a fluorinated dithiophosphoric acid compound havingthe molecular structure according to formula (I):

[0032] wherein R₁ and R₂ are each independently selected from the groupconsisting of fluorinated C₁ to C₄₀ organic residues; and

[0033] wherein R₁ and R₂ are different, or R₁ and R₂ form a ring.

[0034] When prepared in this way, the compounds of the present inventionare generally produced in admixture with compounds where both R₁ and R₂are fluorinated and with other compounds where both R₁ and R₂ arenon-fluorinated. It is generally not necessary to separate or purify thecompounds of the present invention when they are produced in suchmixtures, and they may be used in that form in various applications.

[0035] The process of making anti-wear additives according to theinvention may also include reacting the product of formula (I) with asource of metal atoms to form a metallic salt.

[0036] In yet another embodiment, the present invention includes acomposition comprising a lubricant base fluid and one or morefluorinated anti-wear additives according to formula (I), and/or ametallic salt thereof, wherein R₁ and R₂ are each independently selectedfrom the group consisting of C₁ to C₄₀ organic residues; and furtherwherein at least one of R₁ and R₂ is a fluorinated C₁ to C₄₀ organicresidue.

BRIEF DESCRIPTION OF THE DRAWINGS

[0037]FIG. 1 shows ball-on-cylinder (BOCLE) performance of lubricantcompositions containing non-fluorinated zinc dialkyl dithiophosphates(ZDDPs) in comparison to lubricant compositions containing thefluorinated zinc dialkyl dithiophosphates (F-ZDDPs) of the invention.

[0038]FIG. 2 shows BOCLE performance of lubricant compositionscontaining ZDDPs in comparison to lubricant compositions containing theF-ZDDPs of the invention.

[0039]FIG. 3 shows BOCLE wear performance of a lubricant compositioncontaining an F-ZDDP according to the invention.

[0040]FIG. 4 shows BOCLE wear performance of a lubricant compositioncontaining an F-ZDDP according to the invention.

[0041]FIG. 5 illustrates the low-friction synergy between an F-ZDDP ofthe present invention and a molybdenum dialkyl dithiophosphate.

MODE(S) OF CARRYING OUT THE INVENTION

[0042] The present invention provides compounds useful as anti-wearadditives that, may be used in lubricants, motor oils and otherformulations where resistance to friction and deterioration caused bywear is desired. The compounds of the invention can also be used in anyapplication where antioxidant properties are desired.

[0043] The compounds of the present invention include those representedby the molecular formula (I), and metallic salts thereof:

[0044] wherein R₁ and R₂ are each independently selected from the groupconsisting of C₁ to C₄₀ organic residues;

[0045] wherein R₁ and R₂ are the same or different, or R₁ and R₂ form aring; and wherein at least one of R₁ and R₂ is a fluorinated C₁ to C₄₀organic residue.

[0046] The term “fluorinated”, as it is used herein with respect to theorganic residues, is intended to mean an organic compound containing oneor more fluorine atoms. The term is also intended to include compoundsincluding one or more R_(f) groups, which are hydrocarbyl orhydrocarbyl-containing functional groups wherein one or more hydrogensubstituents have been replaced by fluorine atoms. In this regard, theterm “fluorinated” therefore also includes hydrocarbyl orhydrocarbyl-containing compounds, wherein only some hydrogensubstituents have been replaced by fluorine atoms.

[0047] According to formula (I), above, either or both R₁ or R₂ may bederived from any fluorinated C₁ to C₄₀ organic residue possessing afunctional group that is capable of reacting with the phosphorus atom toform an oxygen linkage. Such fluorinated organic residues may becomprised of hydrocarbyl groups or assemblies of hydrocarbyl groups,each of which may be optionally substituted or linked with atoms and/orfunctional groups that do not interfere with the reactions of thepresent invention. The hydrocarbyl groups, which may be fully orpartially fluorinated, may be selected from straight chain, branched, orcyclic arrangements of one or more carbon atoms connected by single,double, triple, or aromatic bonds and substituted accordingly withhydrogen atoms, which may further be optionally substituted withfunctional groups or atoms that do not interfere with the chemistry ofthe present invention. Assemblies of hydrocarbyl groups, which may alsobe fully or partially fluorinated, comprise one or more such hydrocarbylgroups linked to other hydrocarbyl groups by carbon atoms or by linkagescontaining non-carbon atoms such as B, O, N, S, or P, and may includefunctional groups including, but not limited to ether, thioether, ester,thioester, borate ester, amide, amine, ketone and sulfoxide linkages.Oxygen (ether) linkages, designated herein as —OR, are preferred. Theselinkages may result in cyclic or heterocyclic structures, or may evenconjoin R₁ and R₂ to form a cyclic moiety, such as a diol or polyol.

[0048] Preferably, the organic residue constituting R₁ or R₂ is derivedfrom a fluorinated organic compound including one or more R_(f) groups.Suitable fluorinated C₁ to C₄₀ organic residues used to form R₁ or R₂may be selected from fluorinated alcohols. Most preferably, thefluorinated organic residue is a fluoroalkoxy group derived from afluorinated primary, secondary or tertiary alcohol or phenol, whereinthe alcohol or phenol has an alkyl, cycloalkyl or aryl backboneinclusive of one or more R_(f) groups.

[0049] To form the —OR₁ and —OR₂ linkages in the compounds of formula(I), the fluorinated residues may be selected from fluorinated alcoholshaving the general molecular formula, R_(ƒ)OH, and mixtures thereof,wherein the R_(ƒ) group is as defined above. Typically, a suitablefluorinated alcohol will comprise at least one spacer group between the—OH functionality of the alcohol and the fluorinated hydrocarbyl group,since alpha-fluoroalcohols, such as those containing a —CF₂OH group, arereactively unstable. The spacer group is preferably, but not necessarily—CH₂. Accordingly, suitable fluorinated alcohols that may be used in thepresent invention may be selected from the following species:

[0050] F(CF₂)_(X)CH₂OH, wherein x is from 1 to about 20, such as 1H,1H-heptafluoro-1-butanol and 1H, 1H-perfluoro-1-octanol;

[0051] H(CF₂)_(X)CH₂OH, wherein x is from 1 to about 20, such as 1H, 1H,5H-octafluoro-1-pentanol;

[0052] F(CF₂CF₂)_(X)CH₂CH₂OH, wherein x is from 1 to about 10, such as1H, 1H, 2H, 2H-perfluoro-1-octanol, and mixtures of perfluoroalkanols,examples of which are commercially available from DuPont Inc. under thetradename “ZONYL BA”, having an average value of x of about 4.3, or“ZONYL BA-LD”, which has an average value of x of about 3.7;

[0053] F(CF₂CF₂)_(X)(CH₂CH₂O)_(y)OH, a telomer ethoxylate alcoholwherein x is from 1 to about 10 and y is from 1 to about 20, which ispreferably in the form of a mixture of such alcohols wherein the averagevalue of x is about 3.9 and the average value of y is about 8;

[0054] F(CFCF₃CF₂O)_(X)CF(CF₃)CH₂OH, a poly hexafluoropropylene oxide(HFPO) alcohol wherein x is from 1 to about 20, which is preferably inthe form of a mixture of such alcohols having an average value of x ofabout 6.7.

[0055] Regarding these alcohols, a mixture may be used. Such a mixturemay contain one or more fluorinated alcohols of varying chain length andvarying degrees of fluorination. For example, therefore, where a mixtureof telomeric alcohols is used, minor amounts of longer-chain telomeralcohols may be present along with major amounts of shorter-chaintelomer alcohols.

[0056] Preferred fluorinated alcohols for use in the invention may beselected from 1H, 1H, 2H, 2H-perfluoroalkanols having the molecularformula F(CF₂CF₂)_(X)CH₂CH₂OH, wherein x ranges from 1 to about 20. Mostpreferably, mixtures of 1H, 1H, 2H, 2H-perfluoroalkanols wherein x isfrom 1 to about 5 are preferred. An example of this type of alcohol is1H, 1H, 2H, 2H-perfluoro-1-octanol.

[0057] The non-fluorinated C₁-C₄₀ organic residue may be comprisedpredominantly of hydrocarbyl groups or assemblies of hydrocarbyl groups,each of which may be optionally substituted or linked with atoms and/orfunctional groups that do not interfere with the reactions of thepresent invention. The hydrocarbyl groups may be selected from straightchain, branched, or cyclic arrangements of one or more carbon atomsconnected by single, double, triple, or aromatic bonds and substitutedaccordingly with hydrogen atoms, which may further be optionallysubstituted with functional groups or atoms that do not interfere withthe chemistry of the present invention, in particular halogen atoms.Assemblies of hydrocarbyl groups comprise one or more hydrocarbyl groupslinked to other hydrocarbyl groups by carbon atoms or by linkagescontaining non-carbon atoms such as B, O, N, S, or P, and may includefunctional groups including, but not limited to ether, thioether, ester,thioester, borate ester, amide, amine, ketone and sulfoxide linkages.Oxygen (ether) linkages are preferred. These linkages may result incyclic or heterocyclic structures, or may even conjoin R₁ and R₂ to forma cyclic moiety, such as a diol or polyol.

[0058] Any suitable non-fluorinated C₁ to C₄₀ organic residues may beused to form R₁ or R₂. Such residues may, for example, be selected fromthe group consisting of non-fluorinated alcohols, such that thenon-fluorinated residue is an alkoxy group derived from thenon-fluorinated alcohol, which forms an —OR, or —OR₂ linkage with thephosphorus atom. The non-fluorinated alcohol may be substituted suchthat it comprises an alkyl, cycoalkyl or aromatic backbone.

[0059] Exemplary non-fluorinated alcohols include, but are not limitedto, primary, secondary and tertiary alcohols. Suitable primary alcoholsinclude methanol, ethanol, 1-propanol, 1-butanol, and higher n-alkanolssuch as 1-octanol; and branched primary alcohols such as Oxo or Guerbetalcohols, for example, isotridecanol, which is commercially availableunder the tradename “EXXAL 13” from Exxon, 2-butyl octanol, which iscoomercially available under the tradename “ISOFOL 12” from Condea, orneopentyl alcohol. Suitable secondary alcohols include isopropanol,isobutanol, 4,4-dimethyl 2-pentanol, cyclohexanol, cyclododecanol,2,6-dimethyl-4-heptanol, 3,7-dimethyl-3-octanol and 2-octanol. Suitabletertiary alcohols include t-butanol, and aryl alcohols such as phenoland cresol. The non-fluorinated alcohol may also be selected from diolsand polyols such as ethylene glycol, propylene glycol, 1,4-butane diol,1,5-pentane diol, 1,6-hexane diol, neopentyl glycol, trimethylol propaneand pentaerythritol. Higher alcohols, such as plasticizers, detergentsand fatty alcohols, all of which may be derived from known syntheticprocesses such as the Ziegler, Guerbet and Oxo processes, or by thehydrogenation of natural fats and oils, may also be used.

[0060] Either of the fluorinated or non-fluorinated compounds or bothmay be optionally substituted with functional groups that do notinterfere in the reaction to form the desired oxygen linkages. Forexample, the respective components may contain ether linkages, such asin ethoxylated or propoxylated alcohols. They may also contain linear,branched or cyclic arrangements of atoms and may contain more than onebranched groups that may be the same or different.

[0061] Preferably, at least one of R₁ or R₂ comprises a non-fluorinatedresidue, which may be any non-fluorinated C₁ to C₄₀ organic residuepossessing a functional group that is capable of reacting with thephosphorus atom to form an oxygen linkage. In such an embodiment, theresulting fluorinated compounds of the invention may benon-symmetrically substituted with at least one fluorinated organicresidue and at least one non-fluorinated organic residue. For example, apreferred compound according to formula (I) includes one fluorinatedorganic residue and one non-fluorinated organic residue as substituents.

[0062] As shown in formula (I), the fluorinated and non-fluorinatedsubstituents R₁ and R₂ are bound to the phosphorus atom of athiophosphorus compound by an R—O covalent single bond with an oxygenatom such that the compound of formula (I) are thiophosphorus compoundscomprising at least one fluorinated substituent. Preferably, in formula(I), where R₁ is a fluorinated substituent, R₂ is a non-fluorinatedsubstituent.

[0063] Any suitable thiophosphorus compound may be reacted with thefluorinated and non-fluorinated compound to form the fluorinatedanti-wear additives of the invention. In the reaction to form thecompounds of the present invention, the phosphorus atom may be suppliedby reacting a thiophosphorus compound with at least one fluorinatedcompound and at least one non-fluorinated compound to form one or moreR—O covalent bonds between the phosphorus atom and each of thefluorinated and non-fluorinated compounds. Suitable thiophosphoruscompounds include thiophosphoryl halides and thiophosphoryl anhydrides.The reaction between the fluorinated compounds, non-fluorinatedcompounds and the thiophosphorus compound produces a substitutedthiophosphoric acid or derivative thereof, according to formula (I).Preferably, the thiophosphorus compound is selected from the groupconsisting of thiophosphoric anhydrides. Most preferably, thethiophosphorus compound is phosphorus pentasulfide, which is availablecommercially, for example, from Aldrich Chemical Company, catalog number23,210-6.

[0064] Preferably, the reaction is conducted between a thiophosphoricacid anhydride, P₂S₅, a C₁-C₄₀ fluorinated alcohol and a C₁-C₄₀non-fluorinated alcohol, thereby forming a dialkyl dithiophosphoric acidcompound, which is substituted with at least one fluorine-containingsubstituent and at least one non-fluorine containing substituent.

[0065] The fluorinated compounds of the present invention may beprepared, for example, by first reacting the thiophosphorus compoundwith a limited, less than stoichiometric amount of a fluorinatedreactant, and then reacting the product of the first reaction with anon-fluorinated reactant to complete formation of compounds according toformula (I). Alternatively, a non-fluorinated reactant may be reactedfirst, followed by a non-fluorinated reactant, to form compounds offormula (I). In another alternative, a mixture of at least onefluorinated reactant and at least one non-fluorinated reactant, which ispreferably a mixed-isomer, long-chain, non-fluorinated compound, may bereacted with the thiophosphorus compound in a single step. Theproportions of the fluorinated and non-fluorinated reactants in thecombination of reactants used to make the compounds of the invention mayvary, depending on the specific fluorinated and non-fluorinatedreactants that are selected. The reactants are selected to incorporatesufficient fluorine to provide the resulting compounds with the desiredanti-wear effect, yet retain compatibility with the intended useapplication. For example, where the use application is a lubricantcomposition, the compounds should contain a proportion of fluorine thatrenders them compatible with the lubricant base fluid. Typically, theproportion of fluorinated reactant is from about 1 mole % to about 50mole % of the combined reactants. Additives containing between about 2%weight and 25% weight of fluorine are preferred.

[0066] The reaction used to form the oxygen linkages between thefluorinated and non-fluorinated compounds and the phosphorus atom may beselected from any of the reaction methods known in the art. In somecases particular reaction methods may be more favorable because of rate,and or the ability to remove unwanted byproducts such as hydrogensulfide, which is toxic and malodorous. Preferably, the dialkyldithiophosphoric acids and salts thereof of this invention are preparedby the reaction of a mixture comprising at least one fluorinatedcompound comprising one or more R_(f) groups, and at least onenon-fluorinated compound, with a thiophosphorus compound.

[0067] In a particularly preferred embodiment, one or more fluorinatedalcohols, one or more non-fluorinated alcohols and phosphoruspentasulfide are reacted together to form a dialkyl dithiophosphoricacid compound as the product. Both the fluorinated alcohols and thenon-fluorinated alcohols of the present invention may be furthersubstituted with other functional groups, provided that the addedsubstituents do not interfere with either the reaction with phosphoruspentasulfide to form the dialkyl dithiophosphoric acid, or with anysubsequent reaction to form the metallic salt.

[0068] In such a preferred embodiment, the substituents R₁ and R₂ mayeach be different in that at least one of these substituents isfluorinated and the other is non-fluorinated. The resulting dialkyldithiophosphoric acid compound is therefore non-symmetrical. Suchnon-symmetrical compounds are advantageous in that the presence of thefluorinated substituent provides enhanced tribochemicalfriction-reducing and wear-reducing performance when the compound isused, for example, in a lubricant additive. At the same time, thepresence of the non-fluorinated substituent improves the solubility ofthe compound in typical lubricant base fluids.

[0069] The dialkyl dithiophosphoric acids may be further converted intometallic dialkyl dithiophosphate salts. In this regard, the dialkyldithiophosphoric acids are reacted with a metal or metallic compound topromote conversion to the dithiophosphoric acid salt. Any suitable metalor metallic compound that will form an oil-soluble or oil-dispersiblesalt may be used. Suitably, the metal is an alkali metal, an alkaliearth metal or a transition metal. For example, the source of metalatoms may be a metal or metallic compound of zinc, molybdenum, barium,aluminum, calcium, lithium, lead, tin, copper, cadmium, cobalt,strontium, nickel, or combinations thereof. Preferably, the metal atomis derived from zinc, molybdenum or compounds thereof. Most preferably,the metal atom is derived from zinc metal or from zinc salts including,but not limited to, zinc acetate, zinc oxide and zinc hydroxide.

[0070] The process of making the metallic salts according to theinvention includes combining the product of formula (I) with a puremetal or metallic compound, such as a metallic salt, to cause a reactionforming the metallic dialkyl dithiophosphoric acid salt. If desired,this reaction may be accelerated by heating, for example at refluxtemperature. The basis of the reaction is the neutralization of one ormore dialkyl dithiophosphoric acids with a basic metallic compound ormetal to form a salt. The salt derived from this reaction comprises ametal atom covalently or ionically linked to one or more dialkyldithiophosphoric acid residues, the number of acid residues depending onthe valency of the metal atom. In this respect, the molecular structureof the salt may vary from being a simple binary salt to being acoordination complex having multiple dialkyl dithiophosphoric acidresidues coordinated to the metal atom. Generally, the molecularstructure of a binary salt according to the invention may be representedby the formula (II):

[M ^(X+)][S(S)P(OR)₂]_(x)   (II)

[0071] wherein x is the valency of the metal atom, and the R groups areselected from R₁ and R₂, as defined above, provided that at least one ofR₁ or R₂ is fluorinated. An example of this type of salt is fluorinatedsodium dialkyl dithithiophosphate, represented by the formulaNa[S(S)P(OR)]₂. Transition metal atoms, which have higher valencys, mayform higher molecular weight salts. For example, one fluorinatedmolybdenum compound that may be formed according to the reaction may berepresented as:

[0072] wherein the R groups may be any of R₁ and R₂, as defined above,provided that at least one of R₁ or R₂ is fluorinated. The degree ofsubstitution of the metal atom with the acid residues may also depend onthe stoichiometry of the reaction. According to these factors therefore,numerous possible metallic salts may be formed.

[0073] A typical zinc dialkyl dithiophosphoric acid salt which may beformed according to the invention may be represented by the formula:

[Zn²⁺][S(S)P(OR)₂]₂   (III)

[0074] To form the dithiophosphate salt, a pure metal or metallic saltis added to the reaction mixture containing one or more dialkyldithiophosphoric acids of formula (I), and the resulting mixture isstirred and optionally heated to promote neutralization to the salt,represented as formula (III). For example, fluorinated zinc dialkyldithiophosphates may be prepared using zinc acetate, according to thescheme:

[0075] wherein R₁ and R₂ of formula (I) are as defined above, and R₃,R₄, R₅ and R₆ of formula (III) are C₁-C₄₀ fluorinated or non-fluorinatedorganic residues. Where the substituents R₁ and R₂ are fluorinated ornon-fluorinated, as desired the resulting zinc dialkyl dithiophosphatesof formula (III) may comprise those same substituents as either of R₃,R₄, R₅ or R₆.

[0076] In the formation of zinc dialkyl dithiophosphates according tothe invention, several sources of the metal atom may be used to providethe active metal ion species, however different by-products may beformed as a result of the neutralization reaction.

[0077] Possible zinc sources and the resulting by-products may include:[M] By-product Active species ZnO H₂O Zn²⁺ Zn(OH)₂ H₂O Zn²⁺ Zn metal H₂OZn²⁺ Zn(OAc)₂ acetic acid Zn²⁺

[0078] Similar by-products would be expected where the active species isselected from other suitable metal ions, as described and exemplifiedherein.

[0079] The degree of fluorine substitution in the fluorinated dialkyldithiophosphates may vary according to the degree of initialsubstitution in the compounds of formula (I) and the completeness of thereaction between the fluorinated and unfluorinated residues with thethiophosphoryl compound. Additionally, depending on the position of thefluorinated substituents in the compounds of formula (I), one or moremetallic salts according to formula (II) may be formed, resulting in amixed product. This mixed product may also include unreacted dialkyldithiophosphoric acids in combination with the metallic saltderivatives. Although usually not necessary, if desired, the mixedproducts of the present invention may be purified by centrifugation,distillation, fractional crystallization, filtration, extraction, orother standard methods known to those skilled in the art. For example,the dithiophosphate product may be dissolved in a solvent and lesssoluble impurities may be removed by filtration. Examples of suitablesolvents for this purpose are cyclohexane, toluene or mineral oils. Theresulting product is typically a viscous liquid or waxy solid at roomtemperature.

[0080] The non-symmetrical substitution that may be seen in the dialkyldithiophosphoric acids may also occur in the dithiophosphate saltsformed by neutralization of the acids. Such substitution provides thesame benefits in terms of wear performance and solubility to theresulting dithiophosphate products. Accordingly, the non-symmetricaldialkyl dithiophosphoric acids and dialkyl dithiophosphates of theinvention demonstrate heightened performance both in terms of preventingor reducing wear and with respect to their solubility in lubricatingcompositions.

[0081] Fluorinated metal dithiophosphate salts, and in particular,fluorinated zinc dialkyl dithiophosphate salts (F-ZDDPs) according tothis invention have been found to be useful anti-wear additives inlubricating compositions such as lubricants and motor oils. Moreover,when the zinc dialkyl dithiophosphate salts of the present invention areincluded in a lubricant base oil, the resulting composition is much moreeffective at reducing wear than the base oil alone. It has surprisinglybeen discovered that the fluorinated zinc dialkyl dithiophosphosphatesof the present invention exhibit superior anti-wear properties incomparison to related non-fluorinated zinc dialkyl dithiophosphoricacids or dithiophosphates. Accordingly, use of F-ZDDPs may enableformulation of passenger car motor oil (PCMO) lubricants with reducedphosphorus content, which would reduce phosphorus poisoning of emissionscatalysts. It has also been found that F-ZDDP function at leastsimilarly to, or better than non-fluorinated ZDDPs, in combination withmolybdenum additives useful in low-friction PCMO or other low-frictionlubricant formulations.

[0082] Additionally, in contrast to conventional fluorinated additives,the at least partially fluorinated F-ZDDPs of the present invention aresoluble and compatible with conventional lubricant base fluids such asmineral oils, polyalphaolefins and esters. Conventional fluorinatedlubricants, such as polytetrafluoroethylene (PTFE) or perfluoroethers(PFPE), are typically highly fluorinated, are of high molecular weightand are insoluble in oils. For example, PTFE, a conventional fluorinatedlubricant, contains a fully fluorinated carbon chain, and has amolecular proportion of fluorine ranging from 68% to 76% by weight. Incontrast, the F-ZDDPs of the invention preferably comprise from about 1%by weight to about 50% by weight of fluorine, preferably from about 1%by weight up to about 30% by weight. It has been observed that even avery small amount of the fluorinated alcohol component can impartdramatic wear and friction reducing benefits when F-ZDDPs are used asadditives in lubricant formulations. The presence of a non-fluorinatedalcohol component further enhances the performance of the F-ZDDPs of theinvention. In particular, the non-fluorinated alcohol component of thepreferred F-ZDDPs increases solubility such that they are quite solublein oils, and reduces cost, compared to F-ZDDPs prepared solely fromfluorinated alcohols.

[0083] The function of F-ZDDPs as anti-wear lubricant additives presentssurprising improvements over the use of other conventionally knownfluorinated compounds. ZDDPs, because of their ability to adsorbstrongly to metal wear surfaces, would predictably prevent other typesof anti-wear additives from exerting any surface-modifying effect. It istherefore surprising that incorporation of fluorinated substituents toform F-ZDDPs very significantly improves the performance of thesecompounds in relation to nonfluorinated ZDDPs. It is further surprisingthat these dramatic improvements demonstrated by F-ZDDP performance canbe obtained using only minor amounts of fluorinated substituents incombination with major amounts of nonfluorinated substituents.

[0084] The lubricant compositions of the invention may be prepared bydissolving the fluorinated additives in a suitable lubricant base fluid.Any suitable lubricant base fluid may be used. Preferably, the lubricantbase fluid has a viscosity grade such as might be used for blending ofan oil in an internal combustion engine. The viscosity of the base oildepends on the lubricant application and may vary over a wide range. Therange may be from ISO 10 to ISO 1000, or even higher or lower. For motoroils, the viscosity of the base fluid is suitably in the range of fromISO 10 to ISO 150. One example of a suitable lubricant base fluid is“HYDROCLEAR®”, a hydrocracked mineral base oil fluid having an ISOviscosity of 32, which contains no additives.

[0085] The lubricant compositions can also include one or more otherconventionally known lubricating or anti-wear additives, such ascompletely non-fluorinated metal dialkyl dithiophosphates. For example,various molybdenum dithiophosphates available commercially under thetradename “MOLYVAN” from R.T. Vanderbilt Co. may be added to thecompositions. One such compound is molybdenum, bis[O,O-bis(2-ethylhexyl)phosphorodithioato-S,S′] dioxodi-mu-thioxodi-, (Mo—Mo), availablecommercially as “MOLYVAN-L”. Other soluble molybdenum compounds usefulin lubricant compositions are available from Asahi Denka under thetradename “ADEKA SAKURALUBE”.

[0086] The additives of the invention may also be used in combinationwith other known anti-wear additives, such as non-fluorinated ZDDPS andnon-fluorinated molybdenum anti-wear additives, including molybdenumdialkyl dithiophosphates, molybdenum dialkyl dithiocarbamates andmolybdenum amide complexes. The non-fluorinated molybdenum additives,which are known to reduce the effectiveness of non-fluorinated ZDDPs, doappear to have an adverse effect on wear performance of F-ZDDPs as well,however because F-ZDDPs offer better wear performance thannon-fluorinated ZDDPs, F-ZDDPs may be used with molybdenum additives andstill retain excellent anti-wear performance in comparison to the use ofnon-fluorinated ZDDPs and molybdenum additives.

[0087] The fluorinated additives can be used in desired amounts to givethe desired results. For example, when used in motor oils, the amount ofadditive can range from about 0.1% by weight to about 10% by weight,based on the weight of the motor oil.

[0088] The anti-wear additives of the invention may be combined withother conventional ingredients in a lubricant or passenger car motor oil(PCMO) formulation. A viscosity modifier may be added. Suitableviscosity modifiers include, but are not limited to, olefin copolymerssuch as NORDEL®, polymethacrylates and others. Additionally, one or moreconventional ingredients selected from the group consisting of oxidationinhibitors, pour point depressants, detergents, dispersants, frictionmodifiers, anti-wear agents, foam inhibitors, corrosion inhibitors andmetal deactivators may also be included. Suitably, viscosity modifiersare added to a PCMO at a concentration ranging from about 4% to about15% by weight, while other additives described above may be constitutefrom about 3% to about 15% by weight, although the amounts required toproduce the desired effect in the compositions of the present inventionwould be readily apparent to one skilled in the art.

[0089] The following examples illustrate the present invention, but arenot intended to be limiting.

EXAMPLES

[0090] Fluorinated anti-wear additives of the invention were preparedand evaluated to determine their performance as anti-wear agents. ³¹pchemical shifts were calculated based on spectrometer operatingparameters and represent the approximate chemical shift, in ppm,downfield of external H₃PO₄.

Example 1 Preparation of Zinc Bis [Di-(25 Mole % ZONYL BA, 75 Mole %2-octyl)-dithiophosphate] Using Zinc Acetate

[0091] In a glovebox, a 250-ml 3-necked round bottom flask was chargedwith 5.56 g phosphorus pentasulfide, P₂S₅ (Aldrich), to provide aconcentration of 25 mmol. About 10 ml toluene was used to rinse the P₂S₅down the neck and walls of the flask. The flask was capped with rubbersepta. In a fume hood, a slow counter-flow of dry nitrogen wasintroduced from a needle inserted through one of the rubber septa, andthe flask was fitted with a dropping funnel containing a charge of 10.74g 2-octanol (82.5 mmol), a reflux condenser and a magnetic stir bar. Theoutlet of the reflux condenser was connected via a plastic tubing to acaustic scrubber, then vented to the hood.

[0092] A mixture of 13.2 g ZONYL BA (27.5 mmol), which is a mixture ofperfluorinated alcohols, and 20 ml toluene was warmed in a water bath tomelt and dissolve the perfluorinated alcohol, then this mixture wasadded in one portion to the reaction flask. 2-octanol was then added viathe dropping funnel over 6 minutes, while the reaction mixture washeated, using a heating mantle, from an initial temperature of 47° C. atthe time of addition of the warm toluene and perfluorinated alcoholmixture, to a temperature of 52° C. The mixture was then heated toreflux for about 2.3 hours at a temperature of 110° C. to 115° C. At theend of the reaction, the P₂S₅ had completely dissolved, and an off-whiteproduct was formed that appeared to be more viscous than the productformed in reactions without the fluorinated alcohol, which insteadproduced a clear, green-tinted product. ³¹P NMR (Nuclear MagneticResonance) spectra showed three major signals at chemical shifts of83.9, 85.9 and 87.9 ppm, which were assigned to di-2-octyldithiophosphoric acid, the mixed ZONYL BA-octyl dithiophosphoric acidand di-ZONYL BA dithiophosphoric acid, respectively. From theintegration of the NMR signal, it was evident that the relativeproportions of these three compounds in the mixture was that which wasstatistically predicted, based on the relative amounts of fluorinatedalcohol and 2-octanol used in the preparation.

[0093] The reaction mixture was then cooled to 28° C., after which 5.05g of a solid, anhydrous zinc acetate (27.5 mmol) was added in a singleportion. This mixture was refluxed at a temperature of 110° C. to 115°C. for approximately 3 hours. The product was filtered while warm at atemperature of about 60° C., and the filter rinsed with toluene. Theresulting air-dried filter cake weighed 0.1011 g. The filtrate wasstripped in vacuo to yield 27.47 g of zinc dialkyl dithiophosphate at90% of the theoretical yield.

[0094] The ¹H and ³¹P NMR spectra of the zinc bis[di-(25 mole % ZONYLBA, 57 mole % 2-octyl)-dithiophosphate] were determined. The spectrashowed that the proportion of 2-octyl and fluorinated alcoholsubstituents in the dithiophosphate were consistent with the proportionsexpected from the starting alcohol mixture of 25% fluorinated alcoholand 75% 2-octanol.

Examples 2-6

[0095] Additional fluorinated zinc dialkyl dithiophosphates wereprepared using different combinations of fluorinated compounds,non-fluorinated compounds and zinc sources, and using phosphoruspentasulfide (P₂S₅) as the thiophosphorus compound. Each sample wasprepared analogous to the methodology described for Example 1. Thecombination and proportions of the reactants, and the resulting productF-ZDDP of Examples 2-6, as well as Example 1 are detailed in Table 1,below: TABLE 1 Fluorinated Non-fluorinated compound/ compound/ Zincsource Example F-ZDDP Product (weight) (weight) (grams) 1 Zinc bis[di-25mole % ZONYL ZONYL BA 2-octanol Zinc acetate BA, 75 mole % 2-octyl) 13.2 g 10.74 g 5.05 g dithiophosphate] 2 Zinc bis[di-2.5 mole % ZONYLZONYL BA 2-octanol Zinc acetate BA, 97.5 mole % 2-octyl)  1.32 g 13.97 g5.05 g dithiophosphate] 3 Zinc bis[di-5 mole % ZONYL ZONYL BA 2-octanolZinc acetate BA, 95 mole % 2-octyl)  2.64 g 13.61 g 5.05 gdithiophosphate] 4 Zinc bis[di-10 mole % ZONYL ZONYL BA 2-octanol Zincacetate BA, 90 mole % 2-octyl)  5.28 g 12.89 g 5.05 g dithiophosphate] 5Zinc bis[di-25 mole % ZONYL ZONYL 2-octanol Zinc acetate BA-LD, 75 mole% 2-octyl) BA-LD 10.74 g 5.05 g dithiophosphate] 11.44 g 6 Zincbis[di-25 mole % ZONYL ZONYL BA EXXAL 13 Zinc acetate BA, 75 mole %isotridecanol)  13.2 g (isotridecanols) 5.05 g dithiophosphate] 16.34 g

Comparative Example A Preparation of Non-fluorinated ZDDP, ZincBis(di-2-octyl-dithiophosphate)

[0096] In a glovebox, a 250 ml 3-necked round bottom flask was chargedwith 5.56 g P₂S₅ (25 mmol) and 30 g toluene. The flask was capped withrubber septa and placed in a fume hood. Under a slow counter-flow ofnitrogen from a needle inserted through one of the rubber septa, theflask was fitted with a dropping funnel containing 14.33 g 2-octanol(110 mmol), a reflux condenser and a magnetic stir bar. The outlet ofthe reflux condenser was connected via a plastic tubing to a causticscrubber, then vented to the hood.

[0097] The 2-octanol was added over 11 minutes without external heating,after which the reaction temperature exothermically rose from 28° C. to33° C. The reaction mixture was then heated using a heating mantle andrefluxed at a pot temperature of approximately 115° C. for about 2hours, after which time all the P₂S₅ had dissolved. The reaction mixturewas clear and green. ³¹P NMR in deuterobenzene showed one major signalat 83.9 ppm. This signal was assigned to 2-octyl dithiophosphoric acid.

[0098] After cooling the reaction mixture, an excess of 3.6 grams ofzinc dust (55 mmol, 2.2×theoretical concentration) was added in oneportion. The mixture was stirred, heated and held at reflux for about 2hours. The mixture was cooled, then filtered through a 0.2 micronMillipore® filter. The residual Zn left behind on the filter was rinsedwith toluene, then air-dried. The recovered weight of the air-dried,unused zinc was 2.09 g. The filtrate and toluene rinses were combinedand stripped in vacuo, using a full-pump vacuum, to remove toluene. Theproduct was a clear liquid of a pale blue-green color at a recoveredweight of 19.68 g, which was essentially a quantitative yield. ¹H and³¹P NMR were consistent with the molecular structure of the product.

Comparative Example B Preparation of Non-fluorinated ZDDP, ZincBis(Di-isotridecyl Dithiophosphate

[0099] This comparative example was prepared using the preparationscheme as for Comparative Example A, except that 21.78 g of anisotridecanol mixture, available commercially under the tradename “EXXAL13” from Exxon Chemical Company, was used as the non-fluorinatedalcohol, and in the initial reaction, only 30 g the toluene solvent wasused, all of which was added to the reaction vessel before theisotridecanol was added.

[0100] The following test methods were used to evaluate representativesamples according to the present invention.

[0101] Test Methods

[0102] Samples were tested using the ball-on-cylinder (BOCLE) test overa 30 minute test period, as described in ASTM D5001. Severalmodifications were made to the test, which are summarized in Table 2.These changes were made to make the test a more severe test of anti-wearand friction-modifying properties. Wear was determined according to ASTMD5001, and was quantified by the size of the wear scar on the ball, asmeasured at the end of the testing period. Using this test, a smallerwear scar indicated less wear. The coefficient of friction wascalculated from the ratio of the tangential (lateral) force on the ballto the downward (normal) force on the ball. For each determination ofthis parameter, the reported measurement was the average value duringthe final 26 minutes of the test period, with the first 4 minutesallowed for break-in. In all cases, the normal force was 12,000 grams.TABLE 2 Ball-on-cylinder test conditions Standard ASTM D5001 ModifiedD5001 (consequence) 0.5″ ball 0.25″ ball (smaller contact area) 25° C.80° C. (lower lubricant viscosity) 1000 g load, 30 500 g break in load,0.5 minute, followed by 6000 g test load, minutes 30 minutes (highercontact pressure; note that a 6000 g load produces a 12,000 g normalforce at the ball-cylinder contact point) No friction data Calibratedload cell to measure tangential force on ball during test (allowscalculation of coefficient of friction from ratio of tangential force tonormal force, 12,000 g)

[0103] The relative performance of the materials of the presentinvention as additives in HYDROCLEAR®, a commonly available,high-quality, hydrocracked mineral oil from Conoco, was evaluated. Thegrade of HYDROCLEAR which was used, ISO 32 viscosity grade, is a gradewhich might be used as one component for blending of oil for use in aninternal combustion engine. HYDROCLEAR ISO 32 base oil contains noadditives.

[0104] HYDROCLEAR ISO 32 base oil was tested according to the modifiedBOCLE method numerous times. The average of these results is summarizedin Table 3. TABLE 3 HYDROCLEAR ISO 32 Oil BOCLE results Solvent-refined150N oil Coefficient of friction Wear scar, mm Number of 16 16measurements Average 0.1314 0.905 Standard deviation 0.0052 0.030 95%Confidence ±0.0028 ±0.016 interval

[0105] To determine the efficacy of the additives of the invention inreducing friction and wear, these parameters were measured as a functionof the concentration of F-ZDDP, made according to the invention, in thehydrocracked ISO 32 oil. The F-ZDDPs were prepared to have a constantmolar concentration of phosphorus in each sample.

[0106] For comparative purposes, the friction and wear performance ofseveral commercially available passenger car motor oils formulatedaccording to the International Lubricant Standardization and ApprovalCommittee (ILSAC) GF-1 and GF-2 standards were measured. The GF-1 oilstested included two leading full synthetics, “MOBIL 1 5W30” and Castrol“SYNTEC 5W50”, and one conventional non-synthetic oil, “MOTORCRAFT5W30”. Performance of all three oils was very similar, as is summarizedin Table 4. This may be because all three contained similar amounts ofzinc dialkyldithiophosphate (ZDDP), an extremely effective anti-wearagent. The GF-2 oils tested were from Castrol®, Valvoline®, Pennzoil®,Mobil®, Conoco® and Quaker State®, and represented viscosity grades5W30, 10W30, 10W40, 5W50 and 20W50.

[0107] The level of phosphorus (P) from ZDDPs in GF-1 motor oils istypically about 0.12% (1200 ppm). The current GF-2 motor oils containonly 0.1% P and future generations of oil are expected to contain evenless P. Lower P has adversely affected wear performance, as seen inTable 4. TABLE 4 Commercially Available Motor Oil BOCLE Test ResultsGF-1 Motor Oil GF-2 Motor Oil BOCLE Coefficient of Wear scar,Coefficient of Wear scar, Parameters friction mm friction mm Number of 29 32 32 measurements Average 0.1313 0.499 0.1281 0.544 Standard 0.00290.029 0.0146 0.060 deviation 95% ±0.0260 ±0.022 0.0053 0.022 Confidenceinterval

[0108] These results indicate that the current standard GF-2 motor oil,even containing a conventional anti-wear additive, has a highercoefficient of friction resulting in a larger wear scar, and istherefore less effective at preventing wear.

[0109] To determine the efficacy of the additives made according to thepresent invention, their effect on friction and wear was measured as afunction of their concentration in HYDROCLEAR ISO 32 oil. Generally,there are two approaches to obtaining a given level of fluorine in ablended lubricant. An additive containing a high level of fluorine canbe used at a low treat rate or an additive containing a low level offluorine can be used at a high treat rate. These two approaches do notnecessarily give the same performance.

[0110] The accompanying figures graphically demonstrate the superiorperformance of the fluorinated anti-wear additives of the invention.FIG. 1 shows BOCLE performance for the ZDDP of Comparative Example A andthe F-ZDDPs of Examples 1-4. As seen in Table 1, these compounds wereprepared from various mixtures of ZONYL BA and 2-octanol, wherein themolar percentage of ZONYL BA was varied from zero to 25%. Each of thesamples were tested at a concentration of the additive that would yielda level of about 500 ppm phosphorus, P, in the test fluid. It wasobserved that as the amount of ZONYL increased from zero (ComparativeSample A) to about 25 mole percent (Example 1), the amount of fluorine,F, increased from zero to 23 mole %. According to FIG. 1, there was adramatic reduction of BOCLE wear scar diameter from about 0.9 mm toabout 0.6 mm. All the F-ZDDP samples showed less wear than thenon-fluorinated ZDDP of Comparative Example A.

[0111]FIG. 2 shows BOCLE performance for the ZDDP of Comparative ExampleB, prepared from isotridecanol, and the F-ZDDP of Example 6. Bothsamples were tested in HYDROCLEAR ISO 32 mineral oil at a concentrationsufficient to yield a phosphorus concentration of 500 ppm P. Theperformance of the mineral oil alone, as a control test, is also shown.It is clear from FIG. 2 that using the F-ZDDP formed from thecombination of ZONYL and isotridecanol caused dramatically lower wearthan use of a ZDDP prepared from isotridecanol alone (ComparativeExample B).

[0112]FIG. 3 and FIG. 4 show the BOCLE performance of F-ZDDP fromExamples 5 and 6, respectively. It was observed that, even at lowconcentrations, these additives caused a dramatic reduction of the BOCLEwear scar diameter from about 0.9 mm to from about 0.5 to 0.6 mm.

[0113]FIG. 5 illustrates the low friction synergy between an F-ZDDP ofthe present invention and a commercially available molybdenum dialkyldithiophosphate, MOLYVAN L at 600 ppm (about 0.7% weight). HYDROCLEARmineral oil alone was evaluated as a control test.

[0114] Elemental analysis using standard analytical procedures was alsoperformed for each of metallic salts of Examples 1-6 and ComparativeExamples A and B. These analyses were extremely difficult due tomultiple interferences. Accordingly, CeCl₃, Ag₂O and cation exchangeresins were used to remove P and S interference when determining themolar percentage of F. The molar percentage of each element, as well asthe calculated molar percentage is set forth in Table 5: TABLE 5 CarbonHydrogen Phosphorus Sulfur Flourine zinc Wt. % Wt. % Wt. % Wt. % Wt. %Wt. % (theoretical (theoretical (theoretical (theoretical (theoretical(theoretical Example wt. %) wt. %) wt. %) wt. %) wt. %) wt. %) Comp.51.12 9.02 8.54 16.84 7.83 Ex. A (49.76) (8.87) (8.02) (16.60) (8.46)Comp. 60.3 10.30 6.49 11.65 6.67 Ex. B (59.31) (10.34) (5.88) (12.18)(6.21) 1 37.9 5.40 6.26 12.84 28.77 6.88 (36.19) (4.73) (5.28) (10.94)(31.83) (5.58) 2 48.78 8.66 7.53 12.63 6.11 9.20 (47.93) (8.32) (7.82)(15.87) (4.19) (8.09) 3 47.44 7.53 6.56 15.67 8.56 8.95 (46.26) (7.82)(7.35) (15.21) (8.02) (7.75) 4 44.53 7.21 10.82, 6.25^(a) 12.88, 7.9714.00, 6.57^(a) 8.59 (43.31) (6.93) (6.78) (14.03) (14.80) (7.15) 538.95 5.45 5.69 10.03 22.76 6.72 (37.50) (5.24) (5.86) (12.12) (27.07)(6.18) 6 46.38 6.42 4.14 7.81 19.83 5.49 (43.71) (6.20) (4.48) (9.27)(26.98) (4.73)

[0115] This data reflected the basic characterization of the compoundsof the invention, and established their molecular composition asfluorinated dialkyl dithiophosphates.

[0116] Additional fluorinated zinc dialkyl dithiophosphates andcomparative examples of non-fluorinated zinc dialkyl dithiophosphateswere prepared according to the following schemes:

Comparative Example C Dicyclododecyl Dithiophosphoric Acid and Zinc SaltFrom Cyclododecanol

[0117] In the glovebox, a 250 mL 3-necked round-bottom flask was chargedwith 5.56 g P₂S₅ (25 mmol). About 10 mL toluene was used to rinse P₂S₅down from the neck and walls of the flask. The flask was capped withrubber septa and brought out into the hood. Under a slow counter-flow ofdry nitrogen from a needle inserted through one of the rubber septa, theflask was fitted with a dropping funnel containing 20.28 gcyclododecanol (110 mmol), a cyclic alcohol, and 30.42 g toluene, whichhad been warmed to dissolve the cyclododecanol, reflux condenser, andmagnetic stir-bar. The outlet of the reflux condenser was connected viaplastic tubing to a caustic scrubber, then vented to the hood.

[0118] The solution of cyclododecanol in toluene was added via thedropping funnel, over 21 minutes, while the reaction mixture was heatedwith the heating mantle from ambient temperature to 105° C. The reactionwas heated to reflux (118-120° C.) and held for about 1.4 hours, atwhich time P₂S₅ had dissolved, giving a clear, green solution. ³¹P NMRshowed the major signal to be at 85.0 ppm, assigned to dicyclododecyldithiophosphoric acid.

[0119] After cooling the reaction mixture to 37° C., solid, anhydrouszinc acetate (5.05 g, 27.5 mmol, Aldrich ) was added in one portion. Themixture was heated to reflux for about 2 hours. The product was filteredwhile warm (about 60° C.), and the filter rinsed with toluene. Theair-dried filter cake weighed 0.1641 g. The filtrate was stripped invacuo at about 50° C. to yield the product as a sticky, glassy mass.Elemental analysis, ¹H, and ³¹P NMR spectra were consistent with theexpected product ZDDP composition. The ³¹P NMR spectrum showed the majorsignal to be at 93.7 ppm, assigned to the zinc salt of dicyclododecyldithiophosphoric acid.

Comparative Example D Dicyclohexyl Dithiophosphoric Acid and Zinc SaltFrom Cyclohexanol

[0120] In the glovebox, a 250 mL 3-necked round-bottom flask was chargedwith 5.56 g P₂S₅ (25 mmol) and 20 mL toluene. The flask was capped withrubber septa and brought out into the hood. Under a slow counter-flow ofdry nitrogen from a needle inserted through one of the rubber septa, theflask was fitted with a dropping funnel containing 11.02 g cyclohexanol(110 mmol), reflux condenser, and magnetic stir-bar. The outlet of thereflux condenser was connected via plastic tubing to a caustic scrubber,then vented to the hood.

[0121] The cyclohexanol was added via the dropping funnel, over 3minutes, while the reaction mixture was heated with the heating mantlefrom ambient temperature to 42° C. The reaction was heated to reflux(114-116° C.) and held for about 1 hour, at which time P₂S₅ haddissolved, giving a clear, green solution. ³¹P NMR showed the majorsignal to be at 83.1 ppm, assigned to dicyclohexyl dithiophosphoricacid.

[0122] After cooling the reaction mixture to 29° C., solid, anhydrouszinc acetate (5.05 g, 27.5 mmol, Aldrich ) was added in one portion. Themixture was heated to reflux (108-111° C.) for about 2 hours. Theproduct was filtered while warm (about 60° C.), and the filter rinsedwith toluene. The air-dried filter cake weighed 0.18 g. The filtrate wasstripped in vacuo at about 50° C. to yield the product as an off-whitesolid. Elemental analysis, ¹H, and ³¹P NMR spectra were consistent withthe expected product ZDDP composition. The ³¹P NMR spectrum showed themajor signal to be at 93.7 ppm, assigned to the zinc salt ofdicyclohexyl dithiophosphoric acid.

Comparative Example E Preparation of Di-2-octyl Dithiophosphoric Acidand Zinc Salt By Neutralization With ZnO

[0123] In the glovebox, a 250 mL 3-necked round-bottom flask was chargedwith 5.56 g P₂S₅, 25 mmol, and 30 g cyclohexane. The flask was cappedwith rubber septa and brought out into the hood. Under a slowcounter-flow of dry nitrogen from a needle inserted through one of therubber septa, the flask was fitted with a dropping funnel (containing14.33 g 2-octanol, 110 mmol), reflux condenser, and magnetic stir-bar.The outlet of the reflux condenser was connected via plastic tubing to acaustic scrubber, then vented to the hood.

[0124] The 2-octanol was added over 7 minutes while the reaction washeated from ambient temperature to 37° C. using a heating mantle. Thereaction was heated at reflux (pot temperature approx. 83-87° C.) forapprox. 5 hours, at which time all P₂S₅ had dissolved. The reactionmixture was clear and green. ³¹P NMR showed one major signal at 83.9ppm, assigned to the di-2-octyl dithiophosphoric acid.

[0125] After cooling the reaction mixture, 2.03 g ZnO (25 mmol) wasadded in one portion. The mixture was stirred, heated, and held atreflux for 7.5 hours. The product was cooled, then filtered through a0.2 micron Millipore filter. The white solid retained by the filter,presumably unreacted ZnO, was rinsed with cyclohexane, then air-dried(0.2 g). The filtrate and cyclohexane rinses were combined and strippedin vacuo to remove cyclohexane. The product was a clear liquid with apale blue-green color (18.3 g, 95% of theoretical yield). Elementalanalysis 1H, and 31P NMR data were consistent with the expected ZDDPcomposition. The major signal at about 95 ppm was assigned to Zinc(II)bis(di-2-octyldithiophosphate).

Example 7 Mixed Cyclododecyl-ZONYL BA Dithiophosphoric Acid and ZincSalt From a Mixture of Cyclododecanol and ZONYL BA

[0126] In the glovebox, a 250 mL 3-necked round-bottom flask was chargedwith 5.56 g P₂S₅ (25 mmol). About 10 mL toluene was used to rinse P₂S₅down from the neck and walls of the flask. The flask was capped withrubber septa and brought out into the hood. Under a slow counter-flow ofdry nitrogen from a needle inserted through one of the rubber septa, asolution of 1.23 g ZONYL BA (3 mmol) in 10 g toluene, which had beenwarmed mildly to dissolve the ZONYL BA, was added in one portion, thenthe flask was fitted with a dropping funnel containing 19.77 gcyclododecanol (107 mmol), and 29.66 g toluene, which had been warmed todissolve the cyclododecanol), reflux condenser, and magnetic stir-bar.The outlet of the reflux condenser was connected via plastic tubing to acaustic scrubber, then vented to the hood.

[0127] The solution of cyclododecanol in toluene was added via thedropping funnel, over 11 minutes, while the reaction mixture was heatedwith the heating mantle from ambient temperature to 80° C. The reactionwas heated to reflux (118-120° C.) and held for about 1.5 hours, atwhich time P₂S₅ had dissolved, giving a clear, green solution. ³¹P NMRshowed the major signal to be at 84.6 ppm, assigned to dicyclododecyldithiophosphoric acid. A smaller signal at 86.2 ppm, which was about2.4% the intensity of the major signal, was assigned to the mixedcyclohexyl-ZONYL dithiophosphoric acid.

[0128] After cooling the reaction mixture to 60° C., 5.05 g of solid,anhydrous zinc acetate (27.5 mmol, Aldrich ) was added in one portion.The mixture was heated to reflux (103-113° C.) for about 2 hours. Theproduct was filtered while warm (about 60° C.), and the filter rinsedwith toluene. The air-dried filter cake weighed 0.46 g. The filtrate wasstripped in vacuo at about 50° C. to yield the product as a sticky,taffy-like mass. Elemental analysis, ¹H, and ³¹P NMR spectra wereconsistent with the expected product ZDDP composition. The ³¹P NMRspectrum showed the major signal to be at 93.7 ppm, assigned to the zincsalt of dicyclododecyl dithiophosphoric acid, consistent withComparative Example C. A smaller signal at 96.4 ppm was assigned to thezinc salt of the mixed cyclododecyl-ZONYL dithiophosphoric acid. Thenormalized integrated intensities of the two signals were 96% and 4%,very close to the 95% and 5% statistically expected from the mixture ofalcohols used in the preparation.

Example 8 Mixed Cyclohexyl-ZONYL BA Dithiophosphate and Zinc Salt From aMixture of Cyclohexanol and ZONYL BA

[0129] In the glovebox, a 250 mL 3-necked round-bottom flask was chargedwith 5.56 g P₂S₅ (25 mmol) and 35 g toluene. The flask was capped withrubber septa and brought out into the hood. Under a slow counter-flow ofdry nitrogen from a needle inserted through one of the rubber septa, asolution of 1.32 g ZONYL BA (2.75 mmol) in 15 g toluene, which had beenwarmed mildly to dissolve the ZONYL BA, was added in one portion, thenthe flask was fitted with a dropping funnel (containing 10.74 gcyclohexanol, 107.25 mmol), reflux condenser, and magnetic stir-bar. Theoutlet of the reflux condenser was connected via plastic tubing to acaustic scrubber, then vented to the hood.

[0130] The cyclohexanol was added via the dropping funnel, over 6minutes, while the reaction mixture was heated with the heating mantlefrom ambient temperature to about 63° C. The reaction was heated toreflux (115-117° C.) and held for about 1.4 hours, at which time P₂S₅had dissolved, giving a clear, green solution. ³¹P NMR showed the majorsignal to be at 82.3 ppm, assigned to dicyclohexyl dithiophosphoricacid. A smaller signal at 84.7 was assigned to the mixedcyclohexyl-ZONYL dithiophosphoric acid.

[0131] After cooling the reaction mixture to 29° C., solid, anhydrouszinc acetate (5.05 g, 27.5 mmol, Aldrich ) was added in one portion. Themixture was heated to reflux (111-112° C.) for about 2 hours. Theproduct was filtered while warm (about 60° C.), and the filter rinsedwith toluene. The air-dried filter cake weighed 0.30 g. The filtrate wasstripped in vacuo at about 50° C. to yield the product as an off-whitesolid. Elemental analysis, ¹H, and ³¹P NMR spectra were consistent withthe expected product ZDDP composition. The ³¹P NMR spectrum showed themajor signal to be at 93.9 ppm, assigned to the zinc salt ofdicyclohexyl dithiophosphoric acid. A smaller signal at about 97.5 ppmwas assigned to the zinc salt of the mixed cyclohexyl-ZONYLdithiophosphoric acid, but both signals were too broad for accurateintegration.

Examples 9-12

[0132] Examples 9 and 10 were prepared analogously to Example 7, exceptusing the alcohols and quantities listed in Table 6. Examples 11 and 12were prepared as for Example 8 except using the alcohols and quantitieslisted in Table 6. All dialkyldithiophosphoric acids were characterizedby ¹H and ³¹P NMR, and were determined to be consistent with theexpected compositions. All zinc salt products were characterized byelemental analysis, ¹H, and ³¹P NMR, and were determined to beconsistent with the expected compositions.

Example 13

[0133] In the glovebox, a 250 mL 3-necked round-bottom flask was chargedwith 5.56 g P₂S₅ (25 mmol) and 30 g toluene. The flask was capped withrubber septa and brought out into the hood. Under a slow counter-flow ofdry nitrogen from a needle inserted through one of the rubber septa, theflask was fitted with a dropping funnel (containing 12.89 g 2-octanol,99 mmol, and 4.01 g 1H,1H,2H,2H-perfluorooctanol, 11 mmol), refluxcondenser, and magnetic stir-bar. The outlet of the reflux condenser wasconnected via plastic tubing to a caustic scrubber, then vented to thehood.

[0134] The mixture of alcohols was added via the dropping funnel, over11 minutes, while the reaction mixture was heated with the heatingmantle from ambient temperature to about 93° C. The reaction was heatedto reflux (119-120° C.) and held for about 0.6 hours, at which time P₂S₅had dissolved, giving a clear, green solution. ³¹P NMR showed the majorsignal to be at 83.9 ppm, assigned to di-2-octyl dithiophosphoric acid.A smaller signal at 85.9 was assigned to the mixednonfluorinated-2-octyl—fluorinated-octyl dithiophosphoric acid and aneven smaller signal at 87.8 was assigned to di-fluorinated-octyldithiophosphoric acid.

[0135] After cooling the reaction mixture to 38° C., solid, anhydrouszinc acetate (5.05 g, 27.5 mmol, Aldrich ) was added in one portion. Themixture was heated to reflux (111-113° C.) for about 2 hours. Theproduct was filtered while warm (about 60° C.), and the filter rinsedwith toluene. The air-dried filter cake weighed 0.25 g. Solvent wasremoved from the filtrate in vacuo at about 50° C. to yield the productas a yellow liquid. Elemental analysis, ¹H, and ³¹P NMR spectra wereconsistent with the expected product ZDDP composition. The ³¹P NMRspectrum showed the major signal to be at 93.9 ppm, assigned to the zincsalt of di-2-octyl dithiophosphoric acid. A smaller signal at about 97.9ppm was assigned to the zinc salt of the mixedfluorinated-nonfluorinated dithiophosphoric acid, and a still smallersignal at about 102.9 ppm was assigned to the zinc salt of thedi-fluorinated alcohol dithiophosphoric acid. The integrated intensitiesof these three broad signals were 73:21:6, in reasonable agreement withthe intensities expected statistically from the mixture of alcohols usedin the preparation (81:18:1).

Examples 14-17

[0136] Examples 14 through 17 were prepared using the method used toprepare Example 13, except that the fluorinated alcohols and quantitieswere used as listed in Table 6. All dialkyldithiophosphoric acids werecharacterized by ¹H and ³¹P NMR, which were consistent with the expectedcompositions. All zinc salt products were characterized by elementalanalysis, ¹H, and ³¹P NMR, which were consistent with the expectedcompositions. TABLE 6 Molar proportion of fluorinated alcohol:Fluorinated nonfluorinated Example Nonfluorinated alcohol alcoholalcohol Comparative Cyclododecanol, 20.28 g, none 0:1 Example C   110mmol Comparative Cyclohexanol, 11.02 g, none 0:1 Example D   110 mmolComparative 2-Octanol, 14.33 g, none 0:1 Example E   110 mmol Example 7Cyclododecanol, 19.77 g, ZONYL BA, 1.32 g, 0.025:0.975 107.25 mmol 2.75mmol Example 8 Cyclohexanol, 10.74 g, ZONYL BA, 1.32 g, 0.025:0.975107.25 mmol 2.75 mmol Example 9 Cyclododecanol, 19.26 g, ZONYL BA, 2.64g, 0.05:0.95  104.5 mmol  5.5 mmol Example 10 Cyclododecanol, 18.25 g,ZONYL BA, 5.28 g, 0.1:0.9    99 mmol   11 mmol Example 11 Cyclohexanol,10.47 g, ZONYL BA, 2.64 g, 0.05:0.95  104.5 mmol  5.5 mmol Example 12Cyclohexanol, 9.92 g,  ZONYL BA, 5.28 g, 0.1:0.9    99 mmol   11 mmolExample 13 2-Octanol, 12.89 g, 1H,1H,2H,2H- 0.1:0.9    99 mmolperfluorooctanol, 4.01 g, 11 mmol Example 14 2-Octanol, 12.89 g,1H,1H,5H- 0.1:0.9    99 mmol octafluoropentanol, 2.55 g, 11 mmol Example15 2-Octanol, 12.89 g, 1H,1H- 0.1:0.9    99 mmol heptafluorobutanol,2.20 g, 11 mmol Example 16 2-Octanol, 12.89 g, 1H,1H- 0.1:0.9    99 mmolperfluorooctanol,  4.4 g, 11 mmol Example 17 2-Octanol, 12.89 g,1H,1H,9H- 0.1:0.9    99 mmol perfluorononanol, 4.75 g, 11 mmol

[0137] The following examples show formation of fluorinated dialkyldithiophosphate salts using various metal sources, such as sodiumhydroxide, calcium carbonate, molybdenum acetate, zinc hydroxide andcopper carbonate. It will be apparent to those skilled in the art thatother metal compounds can be similarly used to prepare salts fromfluorinated dialkyl dithiophosphoric acids according to the presentinvention.

Example 18

[0138] A mixed cyclododecyl-ZONYL dithiophosphoric acid is preparedsimilarly to Example 7. The acid is neutralized by addition of zinchydroxide (2.73 g, 27.5 mmol). The product salt is isolated by solventremoval in vacuo.

Example 19

[0139] A mixed cyclododecyl-ZONYL dithiophosphoric acid is preparedsimilarly to Example 7. The acid is neutralized by addition ofmolybdenum (II) acetate (5.9 g, 27.5 mmol Mo equivalent). The productsalt is isolated by solvent removal in vacuo.

Example 20

[0140] A mixed cyclododecyl-ZONYL dithiophosphoric acid is preparedsimilarly to Example 7. The acid is neutralized by addition of sodiumhydroxide (2.2 g, 55 mmol). The product salt is isolated by solventremoval in vacuo.

Example 21

[0141] A mixed cyclododecyl-ZONYL dithiophosphoric acid is preparedsimilarly to Example 7. The acid is neutralized by addition of calciumcarbonate (2.75 g, 27.5 mmol). The product salt is isolated by solventremoval in vacuo.

Example 22

[0142] A mixed cyclododecyl-ZONYL dithiophosphoric acid is preparedsimilarly to Example 7. The acid is neutralized by addition of basiccopper carbonate (3.04 g, 27.5 mmol Cu equivalent). The product salt isisolated by solvent removal in vacuo.

I claim:
 1. A compound according to formula (I) or metallic saltsthereof:

wherein R₁ and R₂ are each independently selected from the groupconsisting of C₁ to C₄₀ organic residues; and wherein R₁ and R₂ aredifferent, or R₁ and R₂ may form a ring, and at least one of R₁ and R₂is fluorinated.
 2. A compound according to claim 1, wherein either R₁ orR₂ is formed from an alcohol independently selected from the groupconsisting of primary, secondary, tertiary or aromatic fluorinatedalcohols and primary, secondary, tertiary or aromatic non-fluorinatedalcohols, such that at least one of R₁ and R₂ is derived from afluorinated alcohol.
 3. A compound according to claim 2, wherein thefluorinated alcohol is selected from the group consisting of alcoholshaving the molecular formulae: F(CF₂)_(X)CH₂OH, wherein x is from 1 toabout 20, H(CF₂)_(X)CH₂OH, wherein x is from 1 to about 20,F(CF₂CF₂)_(X)CH₂CH₂OH, wherein x is from 1 to about 10,F(CF₂CF₂)_(X)(CH₂CH₂O)_(y)OH, wherein x is from 1 to about 10 and y isfrom 1 to about 20, and F(CFCF₃ CF₂O)_(X)CF(CF₃)CH₂OH, wherein x is from1 to about
 20. 4. A compound according to claim 3, wherein thefluorinated alcohol is selected from the group consisting of 1H,1H-heptafluoro-1-butanol and 1H, 1H-perfluoro-1-octanol, 1H, 1H,5H-octafluoro-1-pentanol and 1H, 1H, 2H, 2H-perfluoro-1-octanol.
 5. Acompound according to claim 4, wherein the fluorinated alcohol is 1H,1H, 2H, 2H-perfluoro-1-octanol.
 6. A compound according to claim 2,wherein either R₁ or R₂ is formed from a non-fluorinated alcoholselected from the group consisting of methanol, ethanol, n-propanol,isopropanol, n-butanol, isobutanol, t-butanol, 4-methyl-2-pentanol,2-ethylhexanol, isotridecanol, cyclohexanol, cyclododecanol, phenol,cresol, higher alcohols and fatty alcohols.
 7. A compound according toclaim 1, which is a metallic salt comprising a metal atom selected fromthe group consisting of zinc, molybdenum, barium, aluminum, sodium,calcium, lithium, lead, tin, copper, cadmium, cobalt, strontium, nickeland combinations thereof.
 8. A compound according to claim 1, whereinthe metallic salt comprises a metal atom selected from the groupconsisting of zinc, molybdenum and combinations thereof.
 9. A compoundaccording to claim 1, wherein the metallic salt is zinc.
 10. A compoundof the formula (I) or metallic salts thereof:

wherein R₁ and R₂ are each independently selected from the groupconsisting of C₁ to C₄₀ organic residues; and wherein R₁ and R₂ are thesame or different, or R₁ and R₂ may form a ring, and at least one of R₁and R₂ is a fluorinated C₁ to C₄₀ organic residue, provided that when R₁and R₂ are the same, neither R₁ nor R₂ can be —(CH₂(CF₂)_(x)CF₂H), wherex is 1, 3 or
 5. 11. A lubricant composition comprising a lubricant basefluid and one or more compounds according to claim
 1. 12. An anti-wearadditive comprising one or more compounds of claim
 1. 13. An anti-wearadditive comprising a compound of formula (I) or metallic salts thereof:

wherein R₁ and R₂ are each independently selected from the groupconsisting of C₁ to C₄₀ organic residues; and wherein at least one of R₁and R₂ is a fluorinated C₁ to C₄₀ organic residue.
 14. An anti-wearadditive according to claim 13, wherein the metallic salt is a compoundof the formula (II): [M ^(X+)][S₂P(OR)₂]_(x)   (II) wherein M is a metalatom and x is the valency of the metal atom; wherein the R groups areselected from R₁ and R₂, as defined above, provided that at least one ofR₁ or R₂ is fluorinated.
 15. A process of making an anti-wear additivecomprising: a) preparing a mixture of two or more compounds, whereinsaid mixture includes at least one fluorinated compound and at least onenon-fluorinated compound; b) reacting the mixture with a thiophosphoruscompound to form one or more oxygen linkages between the phosphorus atomof the thiophosphorus compound and each of the fluorinated andnon-fluorinated compounds; and c) recovering a fluorinateddithiophosphoric acid compound having the molecular structure:

wherein R₁ and R₂ are each independently selected from the groupconsisting of fluorinated C₁ to C₄₀ organic residues; and wherein R₁ andR₂ are the same or different, or R₁ and R₂ may form a ring.
 16. Aprocess according to claim 15, further comprising reacting the productof formula (I) with a source of metal atoms to form a fluorinated metaldialkyl dithiophosphate.
 17. A lubricant composition comprising amineral oil base fluid and at least one fluorinated compound accordingto formula (I):

wherein at least one of R₁ and R₂ is a fluorinated C₁ to C₄₀ organicresidue; and wherein R₁ and R₂ are the same or different, or R₁ and R₂may form a ring.
 18. A lubricant composition according to claim 17,further comprising at least one fluorinated dialkyl dithiophosphatesalt.
 19. A lubricant composition according to claim 18, wherein thefluorinated dialkyl dithiophosphate salt is a compound according toformula (II): [M ^(X+)][S₂P(OR)₂]_(x)   (II) wherein M is a metal atomand x is the valency of the metal atom; wherein the R groups areselected from R₁ and R₂, as defined above, provided that at least one ofR₁ or R₂ is fluorinated.
 20. A formulated lubricant for use in internalcombustion engines comprising a lubricant base fluid and at least onefluorinated compound according to claim 1, and optionally comprising oneor more other additives selected from the group consisting of viscositymodifiers, oxidation inhibitors, pour point depressants, detergents,dispersants, friction modifiers, anti-wear agents, foam inhibitors,corrosion inhibitors and metal deactivators.